Crunch! Listen to Philae landing on Rosetta’s comet


Nice crunch! Click the arrow to hear the sound of Philae touching down on Comet 67P/C-G on November 12, 2014. To hear the file as many times as you’d like, click the SoundCloud icon that appears after the first play.

Listen. Hear it? Mixed with the sound of flexing landing pads when Philae first touched down on the comet’s surface is – what sounds to my ear – like the crunch of comet grit. Sensors in the feet of the lander recorded the moment of contact during Philae’s first attempt at landing on November 12th.

It was recorded by the instrument SESAME-CASSE, which was turned on during the descent and clearly registered the first touchdown in the form of vibrations detected in the soles of the lander’s feet. We’re listening to a real sound file - a recording of mechanical vibrations at acoustic frequencies – not a simulation. No changes in frequency were made, so it sounds just the way it would if you could have stuck your head inside Philae with your ear in contact with the landing gear when it made contact with the surface.

Sensors are located in the three feet as well as in the units of the APXS (centre) and MUPUS-Pen (to the upper right of centre) instruments. SESAME stands for Surface Electric Sounding and Acoustic Monitoring Experiment. Click to learn more about the instrument. Credits: ESA/ATG medialab

Klaus Seidensticker from the DLR Institute of Planetary Research says: “Our data record the first touchdown and show that Philae’s feet first penetrated a soft surface layer – possibly a dust layer – several centimeters thick until they hit a hard surface – probably a sintered ice-dust layer – a few milliseconds later.”

Data from SESAME and other instruments indicate that activity in the form of vaporizing ice at Philae’s final landing site is low. Almost all the instruments in the lander did their jobs and returned data to mission control. Early results indicate that organic (carbon-based) molecules were detected, the drill performed as expected and at least went through the motions of delivering a soil sample to the probe’s oven for heating and analysis. What’s unclear is whether it gathered a sample in the first place.

A close up view of Philae’s first landing site on the comet after which it bounced a kilometer high. Scientists are still trying to pinpoint the lander’s final touchdown location. Credit: ESA/Rosetta/OSIRIS

Philae landed on a layer of dust about 4-8 inches (10-20 inches) deep. Beneath this relatively soft cover lies a bitter cold and firm crust of water ice. The MUPUS experiment hammered into the comet as hard as it could but was only able to penetrate a few millimeters. No wonder – the temperature just above the surface measures a nippy –243°F (–153°C). That’s some tough ice!

When the probe was lowered into the dust, the temperature dropped another 10 degrees Celsius.

Rosetta’s orbit, focusing on the maneuvers after November 12th. Credit: ESO

With its batteries drained, Philae’s now in hibernation until at least next spring when the angle of the Sun on the comet will have changed to illuminate the solar panels. Assuming they begin producing electricity to recharge the batteries, there’s a chance we’ll be back in touch and downloading fresh information about the comet by summer.

Meanwhile, the Rosetta orbiter moves to the forefront:

“With lander delivery complete, Rosetta will resume routine science observations and we will transition to the ‘comet escort phase’,” said Flight Director Andrea Accomazzo.

Rosetta will have its “fingers” all over comet 67P/Churyumov-Gerasimenko during the upcoming mapping mission.

Rosetta is expected to stay with the comet at least through December 2015, so we can expect plenty of good science and (hopefully) a lot more close-up photos. On December 3, the craft will move down to a height of just 12.4 miles (20 km) above the surface for about 10 days, after which it will return to 18.6 miles (30 km). Team scientists want to get as close as possible to 67P/C-G before activity from jets of gas and dust becomes too risky to the spacecraft.

The upcoming low orbital volleys will be used to map the icy nucleus at high resolution and collect information on the comet’s gas, dust and plasma (molecules and atoms electrified by the Sun’s UV light).

Quasars Mysteriously Align Across Billions of Light Years

Artist’s rendering of ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun. Some of the matter falling into the hole gets beamed back into space along the axis of the spinning disk’s rotation. Credit: ESO/M. Kornmesser

Quasar. One of the coolest words ever. It’s really shorthand for “quasi stellar radio source”. When radio telescopes were developed in the latter half of the 20th century, astronomers eagerly used them to find new objects in the sky, many invisible in visible light. One of the things they found were these star-like objects glowing brightly in radio waves but appearing only as undistinguished stars in optical telescopes.

Further study revealed they were extremely distant – billions of light years – as far as the most remote galaxies. For such a tiny object to shine across such vast distances, it must be powered by something extraordinary.

We now know that quasars are galaxies with very active supermassive black holes at their centers. Matter falling a black hole gets spun into a whilring disk, releasing tremendous amounts of energy before it finally goes “down the drain” for good. Some the incandescent matter beams back into space in long jets perpendicular to the disk.

This artist’s impression shows the mysterious alignments between the spin axes of quasars and the large-scale structures that they inhabit that observations with ESO’s Very Large Telescope have revealed. These alignments are over billions of light-years and are the largest known in the universe. The large-scale structure is shown in blue and quasars are marked in white with the rotation axes of their black holes indicated with a line. This picture is for illustration only and does not depict the real distribution of galaxies and quasars. Credit: ESO/M. Kornmesser

Today, according to a news announcement by the European Southern Observatory (ESO), a European research team has found that the rotation axes of the central supermassive black holes in a sample of 93 quasars are parallel to each other over distances of billions of light-years. The team has also found that the rotation axes of these quasars tend to be aligned with the vast structures in the cosmic web in which they reside. We see the 93 quasars at a time when the universe was just a third of its current age.

Admittedly, these sounds like pretty obscure stuff, but why should these objects that are not only far from us but billions of light years from each other, be connected? It’s such an intriguing mystery, but before we look at why, let’s stop to examine the large scale structure of the universe.

This simulation, created by the Millennium Simulation Project, represents a 2 billion- light-year-wide chunk of the universe and more than 20 million galaxies. The purple strands represent dark matter around which normal matter (the bright yellow clumps of galaxies) has clustered into filaments of billions of galaxies surrounded by empty voids of space. Credit: Millenium Simulation Project

When we sit back and take in the really, really big picture, the billions of galaxies out there are arranged in dense filaments and strands resembling a pile of spaghetti or neurons in the human brain. The strands in turn are clustered about the still-mysterious dark matter, of which there’s far more of than the bright stuff like stars and galaxies. To refresh your memory, the universe is composed of 73% dark energy, 23% dark matter and only 4% bright matter.

Large pockets of relatively galaxy-free space called cosmic voids lie betwixt and between the strands. The entire texture strikingly shown in the simulation (and visible on smaller scales in maps and photos) is linked to dark matter, which though invisible, is both plentiful and makes its presence known through gravity. Dark matter forms the backbone for all the beautiful galaxies we see in our telescopes and in photos taken by the Hubble. It’s the coral reef and the galaxies are the fish, crabs and all the rest.

Artist concept of a supermassive black hole powering a quasar. Black holes that form from the collapse of a star during a supernova explosion are only a few miles across. Supermassive ones, built up over billions of years from matter straying too close the hole’s event horizon, are the size of the solar system. Our Milky Way harbors such a supermassive black hole, but it’s currently not active like those seen in quasars. Credit: Wiki

The new VLT results indicate that the rotation axes of the quasars tend to be parallel to the large-scale structures in which they find themselves. So, if the quasars are located in one of the spaghetti noodle, then the spins of the central black holes will point along the axis of that noodle. The researchers estimate that the probability that these alignments as simply the result of chance is less than 1%.


Take a journey through the large-scale structure of the universe in this video version of the photo above.

By the way, the research team, led by Damien Hutsemékers from the University of Liège in Belgium, could not see the rotation axes directly but inferred them by measuring the polarization (light waves vibrating in a preferred direction) of the quasars’ light.

So the “why” of these spooky alignments is this: we don’t know … yet:

The alignments in the new data, on scales even bigger than current predictions from simulations, may be a hint that there is a missing ingredient in our current models of the cosmos,” concludes Dominique Sluse.

Are they following the dictates of the unseen dark matter? Hmmm … questions as always. This is the beauty of going where no one has ventured before.

Winter got you down already? Sample spring and a lovely conjunction at dawn

The crescent Moon, just a few days before new, sits atop Virgo’s brightest star, Spica tomorrow morning at dawn. This map shows the sky facing southeast about 50 minutes before sunrise. Stellarium

November nights are long, long, long. You can start the evening with the Summer Triangle, catch wintery Orion at midnight and by dawn it’s already spring! Celestially speaking anyway. Here at 47 degrees north latitude in Duluth, Minn. night takes up the lion’s share of the day with nearly 15 hours of the dark stuff between sunset and sunrise.

If winter’s already nudging into your comfort zone, why not head outside tomorrow morning for a dose of spring stars and a beautiful conjunction of the crescent Moon and Virgo’s brightest luminary, Spica? You can see them even earlier than the map shows when the sky is still dark.

The Moon, just 3 days before new phase, resides in the springtime constellation Virgo. Not far off you’ll also see the little trapezoid of Corvus the Crow. Higher up to the left or north, sparkling Arcturus sputters and twinkles in the cold air.

You can’t stop the Earth from rotating. Once the Sun’s well up in the east, the early summer stars come into view, or they would, if there was no atmosphere. They’re there alright but hidden by scattered sunlight that colors the sky blue. By mid-day, summer’s in full swing. Come sunset, the cycle repeats itself again. And that’s how we roll.

Rosetta captures spectacular photos of Philae drifting above comet

These incredible images show the  Philae lander’s journey as it approached and then rebounded from its first touchdown. You can even see the landing pad impressions (top inset). Pictures taken by the Rosetta OSIRIS camera 9.6 miles (15.5 km) from the surface. Click to enlarge. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Just amazing! And a little sad, too. It’s Philae coming in for its first landing attempt on comet 67P/Churyumov-Gerasimenko. You’ll recall the lander touched down without the use of its reverse thruster or the harpoons to fix it to the surface. Given the near zero-G gravity at the comet, Philae immediately rebounded to the tune of 1 kilometer (0.6 miles) and set off on a brand new path high above the comet. Rosetta was there to see it happen.

Close-up of the first touchdown site before Philae landed (left) and after clearly shows the impressions of its three footpads in the comet’s dusty soil. Times are CST. Philae’s 3.3 feet (1-m) across. Credit: ESA et. all

Rosetta captured Philae’s descent (from left to right) to the comet, the first touchdown point (top inset) and subsequent rebound and drifting off to the right or east. The craft was moving only at a walking pace (1.6 feet/sec) at the time of first contact with the comet. According to the Rosetta blog:

“The mosaic comprises a series of images captured by Rosetta’s OSIRIS camera over a 30 minute period spanning the first touchdown. The time of each of image is marked on the corresponding insets and is in Greenwich Mean Time. A comparison of the touchdown area shortly before and after first contact with the surface is also provided.”

The Rosetta spacecraft spotted Philae and its shadow shortly after the lander touched down and stirred up some dust (dark spot in larger red circle) at 9:30 a.m. (CST). The Philae image was shot five minutes later. Credit: SA/Rosetta/NAVCAM; pre-processed by Mikel Canania

We still don’t know exactly where the lander is, but after two bounces, it finally settled down for good at 11:32 a.m. (CST) a considerable distance east of the original landing site. Expect photos soon of Philae. Mission controllers are hard at work combining the CONSERT ranging data with OSIRIS high resolution and navigation camera images from the orbiter along with photos from Philae’s ROLIS and CIVA cameras to reveal to lander’s location.

Note: The two identical times in the top inset photos are correct even though they both show the same time. When the 15:43 picture was taken, Philae had moved on, but the impressions of its footpads remained.

Lively Leonid meteor shower peaks tomorrow, Tuesday

The annual Leonids peak this week. About a dozen per hour will be visible from a dark site. The shower’s known for fireballs that often leave persistant “smoke trails” or trains. Tony Hallas captured two Leonids in a single frame with glowing trains during the 2001 shower. Credit: Tony Hallas

Watch out for flammable comet dust the next few nights. ‘Tis the season of the Leonids. This annual meteor shower, which originates from dust dribbled by comet 55P/Temple-Tuttle, peaks tomorrow and Tuesday mornings November 17-18.

About every 33 years the Leonids produce a spectacular display. This illustration from a newspaper at the time captures the intensity of the shower on November 13, 1833. The next Leonid storm is expected in 2034.

Every 33 years, when the comet swings into the inner solar system, Leonid numbers swell into the hundreds if not thousands per hour and create what’s better described as a meteor storm. The most recent storm unfolded in 2000-2001; now we’re down to the Leonids’ usual peak of 10-15 per hour.

Admittedly, that’s more like a light drizzle than a shower, but what the Leonids lack in numbers in off-years, they make up for in character. Because the Leonid stream travels around the Sun in a direction opposite to the planets, Earth hits Tempel-Tuttle’s debris head-on at very high speed. Leonids pepper the planet at speeds upwards of 158,000 miles per hour (70 km/sec), the fastest of any shower.

They often burn brightly as fireballs and leave glowing streaks of ionized air in their wakes called trains. Upper atmospheric winds can distort and stretch the trains over several minutes time, a sight well worth watching. In 2001, we saw a fair number of these long-lasting “smoke trails” after the appearance of fireballs.

 

This map shows the sky facing east around 3 a.m. Monday November 17th. The radiant is well-placed near Jupiter in Leo. The thick crescent Moon rises around 2 a.m. Monday and 3 a.m. Tuesday. Stellarium

Watching the Leonids is easy as long as you’re willing to wake up in the wee hours. Patience helps too. You may see nothing in the first 10-15 minutes and then all at once a swift blade of light slices the sky. The radiant or point in the sky from which the meteors originate rises around 11:30 p.m. local time in Leo near Jupiter. But the best time to view the shower is from about 3 a.m. till dawn when the radiant is high in the east-southeast.

Both Monday and Tuesday mornings are good for shower watching. Light from the crescent Moon will hardly be a bother. Dress warmly and get comfy under a blanket in a reclining lawn chair facing east or south. Relax back and watch the stars slowly parade above you. Every meteor you see will come both as a pleasant surprise and reminder that Earth is continually touched by comets.

Sun-planet trio / Sunburned on Jupiter / Giant sunspot returns

Venus, Saturn and the Sun are within 5 degrees of each other in the sky right now. The Sun is hidden behind an occulting disk in this photo taken by the Solar and Heliospheric Observatory last night. Credit: NASA/ESA

It’s happening right now over our heads. Hidden in the solar glare, Venus and Saturn are gathered around the solar hearth today and will be for the next few days. Venus is slowly creeping away from the Sun into evening twilight; Saturn will be in conjunction with the Sun on November 18th and then enter the morning sky.

Jupiter and the third quarter Moon add radiance to the night in the wee hours of November 14th. Credit: Bob King

Did you catch Jupiter two nights ago near the last quarter Moon? From my latitude, they rose about the same time parallel to the horizon and put a sparkle on our freshly-fallen cover of snow.

Recent research on Jupiter’s iconic Great Red Spot (GRS) reveals that its color may have much more to do with the power of sunlight than colorful compounds bubbling up from below.

The GRS is a long-lived, hurricane-like storm first observed by Italian astronomer Giovanni Cassini in 1665.

The results of the new study were presented this week by Kevin Baines, a Cassini team scientist at the American Astronomical Society’s Division for Planetary Science Meeting in Tucson, Arizona.

Jupiter’s Great Red Spot has been around since the early days of the telescope. The large storm, located in the planet’s southern hemisphere, spins once every 4 days. Credit: NASA

Baines and colleagues bombarded ammonia and acetylene, known gases in the planet’s atmosphere, with ultraviolet light to simulate the Sun’s effect on Jupiter’s clouds. This resulted in a red-colored material that proved a good match to the color of the Great Red Spot.

As for why only the GRS and a few other larger oval vortices are red, Baines thinks it has to do with altitude. The Great Red Spot towers 5 miles over the surrounding clouds. Winds from below transport ammonia ice particles to the Spot’s tippy top where they’re exposed to much more of the sun’s ultraviolet light and cooked into the red colors observed in the experiment. In addition, the vortex nature of the spot confines particles, preventing them from escaping and further concentrating the color.

Our old friend, Region 2192, which put on a splendid show during October’s partial solar eclipse, is returning a second time reborn as region 2209 (lower left). This photo taken this morning by the Solar Dynamics Observatory. Credit: NASA/SDO

Guess who’s back darkening the Sun’s face for a second time? Yep – monster sunspot group 2192, now re-numbered 2209, had so much fun the first time, it’s returned for an encore.  Although not as large as a few weeks ago, the group has a complex beta-gamma magnetic field which could produce moderate-strength flares.

Philae, now idle, needs kiss of sunlight to awake

The animated image below provides strong evidence that Philae touched down for the first time almost precisely where intended. The animation comprises images recorded by Rosetta’s navigation camera as the orbiter flew over the (intended) Philae landing site on November 12th. The dark area is probably dust raised by the craft on touchdown. The boulder to the right of the circle is seen in detail in the photo below. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Contact with the Philae lander was lost at 6:36 p.m. (CST) this evening November 14th. Without sunlight to juice up its solar panels and recharge the battery, the craft will remain in “idle mode” – maybe for a long time. All its instruments and most systems on board have been shut down.

“Prior to falling silent, the lander was able to transmit all science data gathered during the First Science Sequence,” says DLR’s Stephan Ulamec, Lander manager. Contrary to earlier reports and initial speculations, Valentina Lommatsch from the German Aerospace Center explained that all three of Philae’s legs are on the ground. But the lander appears to be tipped up at an angle because one of the scenes from the panorama (below) shows mostly sky.

This image was taken by Philae’s down-looking descent ROLIS imager when it was about 131 feet  (40 meters) above the surface of the comet. The surface is covered by dust and debris ranging from millimeter to meter sizes. The large block in the top right corner is 16.4 feet (5 m) in size. In the same corner the structure of the Philae landing gear is visible. Credit: ESA/Rosetta/Philae/ROLIS/DLR

No contact will be possible unless maneuvers by controllers on the ground nudge Philae back into a sunnier spot. On its third and final landing, it unfortunately came to rest in the shadow of one of the comet’s many cliffs.

Jagged cliffs and prominent boulders are visible in this color image taken by OSIRIS, the Rosetta spacecraft’s scientific imaging system, on September 5, 2014 from a distance of 38.5 miles (62 km). Credit: ESA/Rosetta/MPS for OSIRIS team

This evening, mission controllers sent commands to rotate the lander’s main body, to which the solar panels are fixed. This may have exposed more panel area to sunlight, but we won’t know until tomorrow (Nov. 15) at 4 a.m. (CST) when the Rosetta orbiter has another opportunity to listen for Philae’s signal.

Our last panorama from Philae?  This image was taken with the CIVA camera; at center Philae has been added to show how it landed (and took the photos) while on its side. Credit: ESA

The battery was designed to power the probe for about 55 hours. Had Philae landed upright in the targeted region, its solar panels would have been out in the open and soaking up the sunlight needed for multiple recharges. There’s also the possibility that months from now, as seasons progress and solar illumination changes on the comet, the Sun will rise again over the probe.

We may hear from the lander in the coming days or not. But if not, the original plan of gathering as much science as possible in the first two days of landing was for the most part a success.

* UPDATE 7:30 a.m. Nov. 15: Some good news! Rosetta did get back in touch with Philae during the overnight pass. Data was received, but the batteries are expected to be completely drained sometime today.

Philae performs handstand on comet, sends back first panorama

The first panoramic image from the surface of a comet taken by the lander Philae. It’s a 360º view around the point of final touchdown. The three feet of Philae’s landing gear can be seen in some of the frames. Credit: ESA/Rosetta/Philae/CIVA

Beware small comets! Their lack of gravity can make landing hell. The Philae lander finally did settle down on comet 67P/Churyumov-Gerasimenko, but only after two tries. It attempted to touch down just a few hundred feet from the original planned site but with harpoons and rocket thrusters that failed to fire, there was no way for the probe to anchor itself. Instead it dropped to the surface and bounced straight back up into space a full kilometer (0.6 miles) above the comet.

Philae is superimposed on top of the panoramic image. The lander team believes it’s tipped up on its side. Credit: ESA

There it hovered for two hours until dropping down again and rebounding again about 1.5 inches (3 cm) high. In the incredibly low gravity field of the comet, Philae hovered for seven minutes! Then it finally came to rest tipped up on its side in a “handstand” position with one of its legs sticking straight up into outer space.

Stephan Ulamec, Philae Lander manager, describes where the craft landed in a press briefing today. It first touched down in the small red square at left, but then bounced off the comet and settled over two hours later somewhere inside the blue diamond. Credit: ESA

Scientists still hope to figure out a way to right the lander. As you try to make sense of the panorama, keep that in mind. In spite of its awkward stance, Philae’s still able to do a surprising amount of good science. But trouble looms. The craft landed in the shadow of a cliff, blocking sunlight to its solar panels which are used to charge its battery. Philae has one day of full power, which means tomorrow’s a critical day. If the battery runs too low, the probe will go into hibernation mode. The lander team are going to try and nudge Philae into the sunlight by operating the moving instrument called MUPUS tonight.

Philae is that little blip as photographed by Rosetta during the craft’s descent to the comet yesterday. Credit: ESA

Let’s wrap it up with a musical tribute to Rosetta and its mission. Somehow this comet landing, a major achievement despite its minor flaws, deserves a tribute in sound.


Rosetta’s Waltz by Vangelis

 

We’re on the comet, baby! Philae scores a touchdown

Rosetta team members, including  Flight Director Andrea Accomazzo (left), react to the first signal received from the Philae lander after its successful touchdown on Comet Churyumov-Gerasimenko earlier this morning. Credit: ESA

Around 9:37 a.m. (CST) Philae successfully landed on craggy comet Churyumov-Gerasimenko. The first signal, a voice from another world, arrived at 10:05. While the lander reached the surface in good health and continues to send telemetry, a small problem cropped up. The two harpoons that would anchor the craft to the comet failed to fire.

Check out this James Bond-style Swiss Army knife of a lander. Each instrument includes a short description. To read clearly, click for a large version. Credit: ESA

Right now, mission control is considering whether to re-fire them as well as figure out why they didn’t fire in the first place. In the comet’s low gravity, it’s important that Philae be sitting stably. Just think what would happen if a nearby jet erupted or ice began to vaporize around or under the craft? Weighing only a gram, Philae might easily tip over.

Here we come! The photo was taken by Philae at 8:38 a.m. (CST) when it was just 1.8 miles (3 km) above the comet. Credit: ESA/ESA/Rosetta/Philae/ROLIS/DLR

Hopefully we’ll see that first panoramic landscape photo soon. In the meantime, scientists held a press conference this afternoon to share first results as well as some of the troubles the lander faces.

Although Philae landed right on target and is gathering scientific data at this very moment, there have been problems with the radio link. Communications drop in and out for some as-yet unexplained reason. We know that neither the top rocket thruster (used to push the probe to the surface) nor the harpoons fired to anchor the craft to the comet’s surface. The data even seem to indicate that the lander may have even lifted off the ground and landed again:

Just to give you a flavor for the rugged landscape Philae was headed toward earlier today, this photo was taken by Rosetta at an altitude of 4.8 miles (7.7 km) from the comet’s surface. Credit: ESA

“Maybe today we didn’t just land once. We landed twice!” said Stephan Ulamec, Philae Lander Manager. Much is still preliminary, which is why the agency’s scientists are hard at work on the problem. Another live webcast is scheduled tomorrow at 7 a.m. (CST).

Live updates can be had on Twitter and the Rosetta website.

Philae descends to the comet, landing expected soon

The “farewell photo” taken by the Philae lander as it departed Rosetta around 2:30 a.m. (CST) today. It shows the one of the solar arrays on the spacecraft. Credit: ESA/Rosetta/Philae/CIVA

So far, so good. The European Space Agency’s Philae lander, a box of science instruments the size of a dishwasher, is now free-floating to the surface of Comet Churyumov-Gerasimenko and expected to touch down shortly. Lots more updates coming! Be sure to also check the mission’s Twitter feed.

The lander with its legs popped open photographed during its descent to the comet by Rosetta. Credit: ESA/Rosetta/MPS for Rosetta Team